New method to estimate local and system-wide effects of level rail crossings on network traffic flow

This paper makes aggregate estimates of the impacts of removing the large number of at-grade rail crossings (152) in Melbourne, Australia on peak vehicular traffic and congestion. A new method including micro-simulation of a range of rail crossing configurations is used to inform a network model which makes aggregate estimates of impacts on all traffic. Relationships between train frequency and percentage change in vehicle travel time and volume respectively were explored. These equations can predict change in travel time/traffic flow caused by at-grade rail crossings based on estimated rail crossing closure time and train frequency. Overall, Melbourne's at-grade crossings result in an average increase in travel time of 16.1% for vehicle traffic on links with an at-grade crossing. On average an at-grade crossing acts to reduce the volume of vehicles on these links by 5.9% as a result of traffic diversion. The aggregate impact of all 152 at-grade rail crossings on all traffic in Melbourne is a travel time change from 1.81 to 1.82 min/km (an increase of around 0.3%). The number of severely congested links in Melbourne increases by 1.7% while the number of vehicles experiencing congestion increases by 0.7%. These network wide effects are not large compared to localised effects but network effects include representation of traffic diversion impacts which will counter-act some of the immediate impacts on a localised scale.